N-Heterocyclic Carbene-Catalyzed Redox Amidations of α-Functionalized Aldehydes with Amines

Abstract

A catalytic method for the direct synthesis of carboxylic acid amides from amines and α-functionalized aldehydes is possible through the synergistic role of a N-heterocyclic carbene catalyst and imidazole, affording amides via activated carboxylates catalytically generated via an internal redox reaction of the aldehyde substrates. The use of imidazole or other N-heterocycles as an additive is essential to overcoming imine formation and serves as a uniquely reactive substrate for the generation of an acyl imidazolium intermediate that is converted to the final amide product.